An electromagnetic heating device for heating battery pole pieces

Abstract

The present invention discloses an electromagnetic heating device for heating a battery pole piece. The electromagnetic heating device comprises a heating coil (1) and a protective cover (2); the heating coil (1) is arranged in the protective cover (2); a magnetic conductor (3) is arranged inside the protective cover (2); the magnetic conductor (3) surrounds the heating coil (1); and along the length direction of the heating coil (1), a magnetic flux opening (31) is opened on the side of the magnetic conductor (3), and the magnetic conductor (3) is open to surround the heating coil (1); the magnetic conductor (3) is used to guide the magnetic field generated by the heating coil (1) and make the magnetic field pass through the magnetic flux opening (31) uniformly. The electromagnetic heating device of the present invention is used to heat a battery pole piece, and can make the battery pole piece substrate be evenly heated to avoid the phenomenon of uneven heating.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery production, and in particular to an electromagnetic heating device for heating battery pole pieces. Background Art

[0002] The positive electrode substrate of lithium batteries is usually made of aluminum foil. In the roll-pressing production of lithium batteries, the aluminum foil will be wrinkled due to the inconsistency between the elongation of the coating area of ​​the electrode and the aluminum foil, which will cause the electrode to break, prevent normal production and affect product quality. Therefore, it is necessary to heat and soften the electrode substrate of lithium batteries to facilitate the stretching and wrinkle removal of the electrode and ensure that the elongation of the aluminum foil and the coating area is basically consistent.

[0003] However, in the existing lithium battery pole piece rolling production process, a forced stretching method is used to ensure that the aluminum foil and the coating area have basically the same extension. The disadvantages of this method are: the aluminum foil needs to have high tensile strength and no tiny gaps are allowed on the edge, and the compaction density is not high, which cannot meet the large capacity requirements of the battery.

[0004] Magnetic induction heating is a common method for heating metals. This heating method does not require contact with the pole piece, does not affect the travel speed of the pole piece, is highly efficient and energy-saving, and non-contact heating avoids contamination or damage to the pole piece. However, existing methods of electromagnetic heating of pole pieces all fail due to the burning of the aluminum foil or uneven heating due to local low temperatures, which is also the biggest bottleneck in the production of high-capacity lithium batteries. Summary of the invention

[0005] The purpose of the present invention is to provide an electromagnetic heating device for heating a battery pole piece to address the defects or deficiencies in the prior art. The electromagnetic heating device is used to heat the battery pole piece, and can evenly heat the battery pole piece substrate to avoid uneven heating.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] An electromagnetic heating device for heating a battery pole piece comprises a heating coil and a protective cover; the heating coil is arranged in the protective cover; a magnetic conductor is arranged inside the protective cover; the magnetic conductor surrounds the heating coil;

[0008] A magnetic flux opening is provided on the side of the magnetic conductor along the length direction of the heating coil, and the magnetic conductor openly surrounds the heating coil; the magnetic conductor is used to guide the magnetic field generated by the heating coil and make the magnetic induction lines of the magnetic field pass through the magnetic flux opening evenly.

[0009] Preferably, the magnetic conductors are distributed along the inner wall of the protective cover.

[0010] Preferably, the magnetic flux opening is a strip-shaped slot, and the length direction of the strip-shaped slot is consistent with the length direction of the heating coil.

[0011] More preferably, the length of the magnetic flux opening is greater than the length of the heating coil, and the width is greater than the diameter of the heating coil.

[0012] Preferably, both ends of the heating coil pass through the magnetic conductor and the protective cover and extend out of the protective cover;

[0013] Furthermore, the directions in which the two ends of the heating coil penetrate the protective cover are both perpendicular to the directions in which the magnetic induction lines of the magnetic field pass through the magnetic flux opening.

[0014] More preferably, a channel for accommodating the end of the heating coil to extend is opened in the magnetic conductor and in the protective cover, the channel opened in the magnetic conductor is connected with the channel opened in the protective cover, and there is a bending angle of 90° between the channel in the magnetic conductor and the channel in the protective cover.

[0015] More preferably, both ends of the heating coil extending out of the protective cover are connected to power connectors.

[0016] More preferably, the conducting wire of the heating coil is a hollow conducting wire; both ends of the heating coil extend through the protective cover and are respectively used to connect to a cooling water inlet pipe and a cooling water outlet pipe.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] (1) The electromagnetic heating device of the present invention is used to heat the aluminum foil substrate of the battery pole piece, wherein the magnetic field generated by the heating coil can be guided by the magnetic conductor and uniformly pass through the magnetic flux port, and is cut by the battery pole piece substrate to generate uniform eddy current for uniform heating, thereby avoiding edge burning or local temperature failing to meet the temperature requirements.

[0019] (2) When the electromagnetic heating device of the present invention is used to heat the battery electrode, it can evenly heat the battery electrode substrate to avoid uneven heating, and can centrally heat the blank area of ​​the battery electrode, so that the blank area generates high temperature and the coating area generates low temperature, which is more conducive to the stretching and wrinkle removal of the battery electrode while effectively maintaining the stability of the coating area. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the front cross-sectional structure of the electromagnetic heating device of the present invention in a specific embodiment;

[0021] Figure 2It is a schematic diagram of the left side cross-sectional structure of the electromagnetic heating device of the present invention in a specific embodiment;

[0022] Figure 3 It is a schematic diagram of the front cross-sectional structure of the electromagnetic heating device of the present invention in a specific embodiment when it is used to heat a battery electrode;

[0023] Figure 4 It is a schematic diagram of the left-side cross-sectional structure of the electromagnetic heating device of the present invention in a specific embodiment when it is used to heat a battery electrode;

[0024] The attached drawings are marked with: 1-heating coil, 2-protective cover, 3-magnetic conductor, 31-magnetic flux port, 4-power connector, 5-cooling water inlet pipe, 6-cooling water outlet pipe, 7-magnetic induction line, 8-battery pole piece, 801-blank area, 802-coating area, 9-temperature sensor. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings, but the protection scope and implementation methods of the present invention are not limited thereto. In the description of the embodiments of the present invention, it should be noted that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", etc. is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used, and is only used to distinguish the description, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention, let alone an indication or implication of relative importance.

[0026] Example 1

[0027] See also Figure 1 and Figure 2 As shown, the electromagnetic heating device for heating a battery pole piece of this embodiment includes a heating coil 1 and a protective cover 2; the heating coil 1 is arranged in the protective cover 2.

[0028] Moreover, a magnetic conductor 3 is arranged inside the protective cover 2, and the magnetic conductor 3 surrounds the heating coil 1. In this embodiment, the heating coil 1 is a copper coil. Specifically, the protective cover 2 is a closed body structure, and the magnetic conductor 3 is distributed along the inner wall of the protective cover 2; and in this embodiment, the cross-section of the interior of the protective cover 2 is rectangular, and the magnetic conductor 3 is distributed along the inner wall of the protective cover 2 to form a frame-shaped structure with a rectangular cross-section.

[0029] Specifically, along the length direction of the heating coil 1, a magnetic flux opening 31 is opened on the side of the magnetizer 3, so that the magnetizer 3 is open and surrounds the heating coil 1. That is, in this embodiment, the magnetizer 3 is distributed on the front and rear sides, left and right sides, and bottom side of the heating coil 1, and the magnetizer 3 distributed on the front and rear sides, left and right sides, and bottom side of the heating coil 1 is an integrated structure, and the upper side of the heating coil 1 is not distributed with the magnetizer 3, so that the magnetizer 3 is a frame-type structure with an open top and surrounds the heating coil 1 in an open manner, and the magnetic flux opening 31 is the open top of the magnetizer 3.

[0030] The magnetizer 3 is used to guide the magnetic field generated by the heating coil 1, and make the magnetic induction lines 7 of the magnetic field pass through the magnetic flux port 31 uniformly. After the high-frequency and high-voltage current is passed through the heating coil 1, the heating coil 1 will generate a high-speed changing alternating magnetic field. Due to the setting of the magnetizer 3, the magnetic induction lines 7 of the magnetic field will be uniformly reflected and guided by the magnetizer 3; and the magnetic flux port 31 is the open top of the magnetizer 3, so that the magnetic induction lines 7 uniformly reflected and guided by the magnetizer 3 will pass through the magnetic flux port 31 uniformly to the outside of the magnetizer 3, so that the overall device generates a uniform and directional magnetic field; after the battery pole piece substrate cuts the magnetic induction lines 7 emitted by the overall device, a uniform eddy current will be generated in the battery pole piece substrate, thereby achieving uniform heating, avoiding the phenomenon of edge burning or local temperature failing to meet the temperature requirements.

[0031] In this embodiment, the magnetic flux opening 31 is a strip-shaped slot, and the length direction of the strip-shaped slot is consistent with the length direction of the heating coil 1. In addition, the length of the magnetic flux opening 31 is greater than the length of the heating coil 1, the width is greater than the diameter of the heating coil 1, and the height of the magnetizer 3 is greater than the diameter of the heating coil 1. In this way, the magnetic field generated by the heating coil 1 can be guided and reflected under the action of the magnetizer 3, and at the same time can pass through the magnetic flux opening 31 to the outside of the magnetizer 3, which is conducive to fully utilizing the magnetic field and greatly improving the working efficiency of the heating coil 1.

[0032] In addition, both ends of the heating coil 1 penetrate the magnetic conductor 3 and the protective cover 2 and extend out of the protective cover 2 . Among them, a channel for accommodating the end of the heating coil 1 to extend is opened in both the magnetizer 3 and the protective cover 2, and the channel opened in the magnetizer 3 is connected with the channel opened in the protective cover 2 to accommodate the end of the heating coil 1 to extend; and there is a bending angle of 90° between the channel in the magnetizer 3 and the channel in the protective cover 2, so that the end of the heating coil 1 passes through the magnetizer 3 and the protective cover 2 in turn and forms a 90° bend between the two before extending, so that the direction in which the two ends of the heating coil 1 pass through the protective cover 2 is perpendicular to the direction in which the magnetic induction lines 7 of the magnetic field pass through the magnetic flux opening 31; and there is a sealed filling between the outer wall of the end of the heating coil 1 and the channel in the magnetizer 3 and the channel in the protective cover 2; in this way, by bending the end of the heating coil 1 90° before extending it, and sealing and filling between the outer wall and the channel, the magnetic field generated by the heating coil 1 can be effectively prevented from leaking, and the occurrence of magnetic leakage can be avoided, which is conducive to fully utilizing the magnetic field generated by the heating coil 1 and further improving the working efficiency of the heating coil 1.

[0033] Power connectors 4 are connected to the ends of the heating coil 1 extending out of the protective cover 2. The heating coil 1 is connected to an external high-frequency high-voltage power supply through the power connector 4, thereby providing the heating coil 1 with power to generate an alternating magnetic field.

[0034] Furthermore, the conducting wire of the heating coil 1 is a hollow conducting wire. Both ends of the heating coil 1 extend out of the protective cover 2 and are respectively used to connect the cooling water inlet pipe 5 and the cooling water outlet pipe 6. In the process of the heating coil 1 being connected to high-frequency and high-voltage electricity for electromagnetism, the heating coil 1 will generate high temperature due to its own resistance; therefore, by using a hollow conducting wire as the conducting wire of the heating coil 1, and connecting the cooling water inlet pipe 5 and the cooling water outlet pipe 6 at both ends of the heating coil 1, when the heating coil 1 is performing electromagnetism, circulating cooling water can be introduced to cool the heating coil 1, thereby avoiding the safety hazard of burning or fire caused by excessive temperature of the heating coil 1, and improving the safety performance and service life of the overall electromagnetic heating device.

[0035] See also Figure 3 and Figure 4As shown, the electromagnetic heating device of this embodiment is used to heat the battery pole piece substrate. The substrate of the battery pole piece 8 is aluminum foil; the magnetic flux port 31 is arranged corresponding to the battery pole piece 8, the battery pole piece 8 is located above the electromagnetic heating device, and the length direction of the magnetic flux port 31 is consistent with the moving direction of the battery pole piece 8; during the movement of the battery pole piece 8, the substrate of the battery pole piece 8 will evenly cut the magnetic induction line 7 emitted by the electromagnetic heating device to generate a uniform eddy current, thereby evenly heating the substrate of the battery pole piece 8, avoiding the phenomenon of uneven heating, achieving softening of the substrate of the battery pole piece 8, and facilitating the stretching and wrinkle removal of the battery pole piece substrate.

[0036] Moreover, in a preferred embodiment, a temperature sensor 9 corresponding to the electromagnetic heating device can be arranged above the battery electrode 8 to perform real-time detection and monitoring of the temperature; and the temperature sensor 9 and the electromagnetic heating device can be connected through a controller for closed-loop control, so that the temperature detected by the temperature sensor 9 can perform closed-loop feedback control on the electromagnetic heating device, thereby further improving the control of the heating temperature of the substrate of the battery electrode 8.

[0037] And, in specific applications, see Figure 4 As shown, the electromagnetic heating device of this embodiment can centrally heat the blank area 801 of the battery pole piece 8, so that the blank area 801 generates a high temperature, while the coating area 802 generates a low temperature. Specifically, the magnetic flux port 31 of the electromagnetic heating device is correspondingly arranged directly below the blank area 801 of the battery pole piece 8, so that the magnetic flux penetrating from the blank area 801 is greater than the magnetic flux penetrating from the coating area 802, so that during the movement of the battery pole piece 8, the eddy current generated by the substrate of the blank area 801 cutting the magnetic induction line 7 will be greater than the eddy current generated by the substrate of the coating area 802 cutting the magnetic induction line 7, thereby making the heating temperature of the substrate of the blank area 801 greater than the heating temperature of the substrate of the coating area 802.

[0038] In the battery pole piece 8, the wrinkle rate of the blank area 801 is usually high, while the wrinkle rate of the coating area 802 is low, and if the coating area 802 is at a high temperature, it is not conducive to the stability of the coating. In this way, by centrally heating the blank area 801, the blank area 801 is made to generate a high temperature, so as to meet the softening treatment requirements for stretching and wrinkle removal of the blank area 801 substrate, while the coating area 802 is made to generate a low temperature, which is more conducive to the stretching and wrinkle removal of the battery pole piece 8, and can also effectively maintain the stability of the coating area 802.

[0039] The above embodiments are only preferred embodiments of the present invention and are only intended to further describe the technical solutions of the present invention in detail. However, the protection scope and implementation methods of the present invention are not limited thereto. Any changes, combinations, deletions, replacements or modifications made without departing from the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electromagnetic heating device for heating battery pole pieces, It is characterized in that The invention comprises a heating coil (1) and a protective cover (2); the heating coil (1) is arranged in the protective cover (2); a magnetic conductor (3) is arranged inside the protective cover (2); the magnetic conductor (3) surrounds the heating coil (1); and a magnetic flux opening (31) is provided on the side surface of the magnetic conductor (3) along the length direction of the heating coil (1), and the magnetic conductor (3) surrounds the heating coil (1) in an open manner; the magnetic conductor (3) is used to guide the magnetic field generated by the heating coil (1) and make the magnetic induction lines of the magnetic field pass through the magnetic flux opening (31) uniformly; Both ends of the heating coil (1) penetrate the magnetizer (3) and the protective cover (2) and extend out of the protective cover (2); a bending angle of 90° exists between the hole in the magnetizer (3) and the hole in the protective cover (2); and the outer wall of the end of the heating coil (1) and the hole in the magnetizer (3) and the hole in the protective cover (2) are sealed and filled; Furthermore, the directions in which the two ends of the heating coil (1) penetrate the protective cover (2) are both perpendicular to the directions in which the magnetic induction lines of the magnetic field pass through the magnetic flux opening (31).

2. An electromagnetic heating device for heating a battery pole piece according to claim 1, It is characterized in that The magnetic conductors (3) are distributed along the inner wall of the protective cover (2).

3. An electromagnetic heating device for heating a battery pole piece according to claim 1, It is characterized in that The magnetic flux opening (31) is a strip-shaped slot, and the length direction of the strip-shaped slot is consistent with the length direction of the heating coil (1).

4. An electromagnetic heating device for heating a battery pole piece according to claim 3, It is characterized in that The length of the magnetic flux opening (31) is greater than the length of the heating coil (1), and the width is greater than the diameter of the heating coil (1).

5. The electromagnetic heating device for heating a battery pole piece according to claim 1, It is characterized in that Both ends of the heating coil (1) extending through the end portions outside the protective cover (2) are connected to power connectors (4).

6. The electromagnetic heating device for heating a battery pole piece according to claim 1, It is characterized in that The conducting wire of the heating coil (1) is a hollow conducting wire; both ends of the heating coil (1) extend through the protective cover (2) and are respectively used to connect to a cooling water inlet pipe and a cooling water outlet pipe.

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